The role of complement component 3 in red blood cell alloimmunization

补体成分 3 在红细胞同种免疫中的作用

• 批准号: 9258323
• 负责人: Amanda Mener
• 金额: $ 4.9万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9258323
• 关键词: Acute; Adaptive Immune System; Alloantigen; Alloimmunization; Antibodies; Antibody Formation; Antibody Response; Antigens; Applications Grants; Blood Transfusion; Cell surface; Cells; Cessation of life; Complement; Complement 3; Complement 3d; Data; Deposition; Development; Disease; Erythrocyte Transfusion; Erythrocytes; Excision; Female; Fetus; Foundations; Future; Glycoproteins; Goals; Hemoglobinuria; Human; Immune response; Immunize; Immunologics; Incubated; Individual; Isoantibodies; Kinetics; Knock-out; Knockout Mice; Lead; Masks; Mediating; Modeling; Mus; Newborn Infant; Partner in relationship; Pathway interactions; Phase; Placenta; Play; Process; Prophylactic treatment; Reaction; Resistance; Resistance development; Risk; Role; Testing; Therapeutic; Transfusion; United States; Wild Type Mouse; blood group; clinically relevant; combat; complement C3d,g; cytokine; design; experimental study; immunogenic; insight; male; mouse model; novel; novel strategies; prevent; public health relevance; response

 DESCRIPTION (provided by applicant): Repeated blood transfusions can lead to formation of alloantibodies against RBC alloantigens, antigens on the RBC surface capable of inducing antibody formation in individuals who lack the particular antigen. These RBC alloantibodies increase the risk of hemolytic transfusion reactions and make it difficult to find compatible RBCs for future transfusions. However, the mechanism(s) of how RBC alloantigens induce alloantibodies and the potential pathways responsible for RBC clearance following incompatible transfusions remain poorly understood. The KEL glycoprotein is one of the most immunogenic RBC alloantigens and is also one of the most common alloantigens implicated in hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Therefore, we developed a mouse model that expresses the human KEL glycoprotein specifically on murine RBCs to understand the factors that contribute to the development and consequences of RBC-induced alloantibody formation. In preliminary results, we found that transfusion of KEL RBCs into KEL immunized C57BL/6 (wild-type) recipients results in a rapid clearance phase, followed by an abrupt change in clearance kinetics, such that the remainder of the KEL RBCs develop resistance to further antibody-mediated clearance. KEL RBCs transfused into immunized recipients displayed significant alterations to the KEL antigen that paralleled the development of RBC resistance, suggesting a role of antigen modulation in the protection of RBCs from additional antibody-mediated removal. Given the potential involvement of complement not only in facilitating antibody-mediated clearance, but also in antigen modulation, we examined the potential role of complement in this process. We found that although KEL antigen levels decrease following transfusion of incompatible KEL RBCs in wild-type mice, KEL expression levels remain unaltered in immunized complement component 3 (C3) knockout KO mice, strongly suggesting that complement may facilitate antigen modulation. Given the ability of anti-KEL antibodies to engage complement and the role of C3 in enhancing antibody formation to other antigens, we examined the potential impact of complement in the development of anti-KEL antibodies following KEL RBC transfusion. In contrast to previous studies, we found that transfusion of KEL RBCs into C3 KO mice actually resulted in a significant increase in anti-KEL antibody formation. Given the ability of C3 to modulate the KEL antigen following incompatible transfusion and the increased levels of anti- KEL antibody that form following transfusion into C3 KO recipients, we hypothesize that complement deposition may mask the KEL antigen from immunologic recognition following incompatible RBC transfusion and reduce the ability of the adaptive immune system to efficiently recognize and therefore respond to the KEL antigen. These fundamental studies will not only define the role of complement in KEL RBC clearance and alloimmunization, but will also provide novel insight into potential therapeutic strategies designed to combat the deleterious effects of RBC alloimmunization.

 描述（由申请人提供）：重复输血可导致形成针对RBC同种抗原的同种抗体，RBC表面上的抗原能够在缺乏特定抗原的个体中诱导抗体形成。这些红细胞同种抗体增加了溶血性输血反应的风险，并使其难以找到相容的红细胞用于未来的输血。然而，RBC同种异体抗原如何诱导同种异体抗体的机制以及不相容输血后RBC清除的潜在途径仍然知之甚少。KEL糖蛋白是最具免疫原性的RBC同种异体抗原之一，也是涉及溶血性输血反应和胎儿和新生儿溶血性疾病的最常见同种异体抗原之一。因此，我们开发了一种小鼠模型，表达人KEL糖蛋白特异性对小鼠红细胞了解的因素，有助于红细胞诱导的同种抗体形成的发展和后果。在初步结果中，我们发现将KEL RBC输注到KEL免疫的C57 BL/6（野生型）受体中导致快速清除阶段，随后清除动力学发生突然变化，使得KEL RBC的剩余部分对进一步的抗体介导的清除产生抗性。输注到免疫受体的KEL RBC显示出KEL抗原的显著改变，这抑制了RBC抗性的发展，表明抗原调节在保护RBC免受额外抗体介导的去除中的作用。鉴于补体不仅可能参与促进抗体介导的清除，而且可能参与抗原调节，我们研究了补体在此过程中的潜在作用。我们发现，虽然KEL抗原水平下降不兼容KEL红细胞输注野生型小鼠，KEL表达水平保持不变免疫补体成分3（C3）基因敲除小鼠，强烈表明，补体可能有助于抗原调节。鉴于抗KEL抗体与补体结合的能力以及C3在增强针对其他抗原的抗体形成中的作用，我们检查了补体在KEL RBC输注后抗KEL抗体产生中的潜在影响。与以前的研究相反，我们发现将KEL RBC输注到C3 KO小鼠中实际上导致抗KEL抗体形成的显著增加。考虑到C3在不相容输血后调节KEL抗原的能力以及在输注到C3 KO受体后形成的抗KEL抗体水平增加，我们假设补体沉积可能在不相容RBC输注后掩蔽KEL抗原而使其不被免疫识别，并降低适应性免疫系统有效识别KEL抗原并因此对KEL抗原作出应答的能力。这些基础研究不仅将确定补体在KEL RBC清除和同种异体免疫中的作用，而且还将为旨在对抗RBC同种异体免疫的有害影响的潜在治疗策略提供新的见解。